All look like Chalcedony varieties to me. Which means they are all microcrystalline quartz. To differentiate by type we need to look at banding, translucency, and color.
Judging from the pictures,
I would classify 5, and 6 as agate based on the translucency, and wavy/curved banding. I would call 1,4,3 Jasper based on pattern and low translucency. I would call 2 Sardonyx based on the brown color with straight banding.
Making the call on variety in Chalcedony is often where I would disagree with GIA during the GG course. But oh well, the difference has no monetary consequences.
I would concur, all seem to be varieties of SiO2. No 2 is interesting, cabochons cut from dark stones used to be cut that way to lighten them, but I haven't seen an example in many years.
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